Devices that capture data from various combinations of sensors are used in many applications. Such devices including sensors that require alignment or calibration are generally aligned or calibrated in the factory. The devices are generally suitable for performing a specific dedicated task but not suitable for other purposes. This leads to high cost and for some applications the cost cannot be justified.
It is an object of the invention to provide a device for augmenting the sensors provided in standard consumer electronics devices within a compact housing, the resulting instrument being capable of capturing images and precise positional data.
It is a further object of the invention to provide a device that enables user alignment of a camera and laser rangefinder.
It is a further object of the invention to provide a device that enables user alignment of a camera, laser rangefinder and one or more orientation sensors.
Each object is to be read disjunctively with the object of at least providing the public with a useful choice.
Exemplary Embodiments
According to one exemplary embodiment there is provided a data capture method including: mounting a rangefinder module to a portable device, the rangefinder module including a laser rangefinder emitting and detecting a rangefinder beam and the portable device including a camera and a display, such that, in a mounted state, the laser rangefinder and camera are in fixed relation to each other. A direction of the laser rangefinder is determined by: capturing one or more alignment images using the camera; determining from the image or images a position of the rangefinder beam in the image or images; and determining from the position a laser rangefinder direction relative to the camera. Data is captured by: displaying an image from the camera on the display with a marker, the marker and the determined laser rangefinder direction being aligned such that the apparatus is arranged to be pointed by a user towards a target by aligning the marker with the target; and capturing substantially simultaneously an image including the target using the camera and a range to the target using the laser rangefinder.
An alignment range may be captured using the laser rangefinder, substantially simultaneously with the one or more alignment images, the laser range finder direction being determined from the position and alignment range.
The rangefinder beam may be an infrared laser beam and the camera may be sensitive to visible and infrared light.
Detection of the rangefinder beam may be enhanced by reducing the amount of visible light entering the camera. The step of reducing the amount of visible light entering the camera may include temporarily positioning an infrared pass visible blocking filter in front of the camera.
Alternatively, a visible laser beam with a known relationship to the rangefinder beam may be projected, the step of determining from the image or images a position of the rangefinder beam in the image or images including determining the position of the visible laser beam and determining the position of the rangefinder beam based on the position of the visible laser beam and the known relationship.
Alternatively, the step of determining from the image or images a position of the rangefinder beam in the image or images may include subtracting a visible background to enhance detection of the infrared laser rangefinder beam. The background may be determined from a first image captured by the camera in the absence of the laser rangefinder beam.
Multiple pulses of the laser rangefinder beam may be detected per frame captured by the camera to enhance detection of the infrared laser rangefinder beam.
Alternatively, data may be accumulated over multiple camera frames to enhance detection of the infrared laser rangefinder beam.
Alternatively, a target may be provided, at least partly formed form a material that converts infrared light to visible light, at least one of the alignment images being captured with the laser rangefinder aligned with the target, and determining from the image or images a position of the rangefinder beam in the image or images includes detecting the visible light emitted by the target material.
The step of capturing substantially simultaneously one or more alignment images using the camera and an alignment range using the laser rangefinder may be performed in a darkened space.
The step of capturing substantially simultaneously one or more alignment images using the camera and an alignment range using the laser rangefinder may be performed two or more times at different ranges.
The marker and the determined laser rangefinder direction may be aligned by either: displaying a marker in alignment with the determined laser rangefinder direction whether or not that direction is offset from a display centre; or displaying a marker at the display centre and aligning a displayed image to bring the laser rangefinder direction to the display centre.
The rangefinder module or the portable device may include a positioning system and one or more orientation sensors, the step of capturing data including capturing a position of the rangefinder module or portable device using the positioning system and an orientation of the rangefinder module or portable device using the orientation sensors substantially simultaneously with capture of the image and range.
Before capturing data, the one or more orientation sensors may be aligned with the laser rangefinder direction.
This alignment may be performed by: capturing a first set of orientation parameters with the portable apparatus in a first position and a first orientation while aiming the portable apparatus at a second position; capturing a second set of orientation parameters with the portable apparatus in the first position and a second orientation while aiming the portable apparatus at the second position; capturing a third set of orientation parameters with the portable apparatus in the second position and the first orientation while aiming the portable apparatus at the first position; capturing a fourth set of orientation parameters with the portable apparatus in the second position and the second orientation while aiming the portable apparatus at the first position; and from the differences between the four sets of orientation parameters, determining one or more offsets for the one or more orientation sensors.
Captured data may be communicated from the rangefinder module to the portable device.
According to another exemplary embodiment there is provided, in a measurement apparatus including: a portable device including: a camera; a display; a processor; and memory; and a rangefinder module including: a laser rangefinder emitting a rangefinder beam; and a mounting arrangement for mounting the rangefinder module to the portable device such that, in a mounted state, the laser rangefinder and camera are in fixed relation to each other; the apparatus being configured to implement a wired or wireless communications link between the portable device and the rangefinder module; a method including: determining a direction of the laser rangefinder by: capturing one or more alignment images using the camera; determining from the image or images a position of the rangefinder beam in the image or images; and determining from the position a laser rangefinder direction relative to the camera; and capturing data by: displaying an image from the camera on the display with a marker, the marker and the determined laser rangefinder direction being aligned such that the apparatus is arranged to be pointed by a user towards a target by aligning the marker with the target; and capturing substantially simultaneously an image including the target using the camera and a range to the target using the laser rangefinder.
According to another exemplary embodiment there is provided a computer readable medium having encoded thereon computer readable instructions that when executed on a portable device including a processor, a camera and a display, with an attached laser rangefinder module, are arranged to: cause, in response to detection of an alignment capture instruction: capture of one or more alignment images using the camera; the processor to determine from the image or images a position of the rangefinder beam in the image or images; and the processor to determine from the position a laser rangefinder direction relative to the camera; and cause a marker and the determined laser rangefinder direction to be aligned such that the apparatus is arranged to be pointed by a user towards a target by aligning the marker with the target; and cause, in response to a data capture instruction: substantially simultaneous capture of an image including the target using the camera and a range to the target using the laser rangefinder.
According to another exemplary embodiment there is provided a method of aligning a camera and one or more orientation sensors in a portable apparatus, including: capturing a first set of orientation parameters with the portable apparatus in a first position and a first orientation while aiming the portable apparatus at a second position; capturing a second set of orientation parameters with the portable apparatus in the first position and a second orientation while aiming the portable apparatus at the second position; capturing a third set of orientation parameters with the portable apparatus in the second position and the first orientation while aiming the portable apparatus at the first position; capturing a fourth set of orientation parameters with the portable apparatus in the second position and the second orientation while aiming the portable apparatus at the first position; from the differences between the four sets of orientation parameters, determining one or more offsets for the one or more orientation sensors.
Preferably the one or more offsets are stored in memory.
Preferably a marker is displayed on a display of the portable apparatus, the marker being overlaid on an image from the camera, wherein aiming the portable apparatus involves aligning the marker with the first or second position.
According to a further exemplary embodiment there is provided a laser range finder module configured for attachment to a portable device including a camera having an optical axis, the module including: a laser range finder substantially aligned on a rangefinder axis; and one or more optical elements positioned to redirect light so as to substantially align the rangefinder axis and a camera optical axis when the laser range finder module is mounted on a portable device.
Preferably the laser rangefinder module includes a mounting arrangement configured to mount the laser rangefinder module to a portable device.
Preferably a folded optical path is employed to reduce the thickness of the laser rangefinder and the volume occupied by optical components. A first folded optical path from the range finder axis to the laser receiver may be formed by optical elements including two or more mirrors, with a first preferably inclined at an angle of between 50 to 60 degrees to the rangefinder axis. A second mirror is preferably provided substantially parallel to the first mirror. The first folded optical path preferably directs received light onto a surface mounted laser receiver.
The orientation of the first and/or second mirrors may be adjustable with respect to the rangefinder module to achieve focus and/or alignment.
A Fresnel lens is preferably provided in the optical path prior to the first mirror.
The grooves of the Fresnel lens may face away from the first mirror, in which case it is desirable to provide a cover window over the Fresnel lens, or the grooves may face towards the first mirror, which is a simpler implementation although optically inferior. When a cover window is employed the Fresnel lens preferably includes a nipple to keep the cover window spaced apart from the Fresnel lens to avoid the incidence of Newton's rings.
Optical coatings are preferably provided on interior surfaces of the Fresnel lens and/or cover window. The optical coatings preferably have a pass band of about 905 nm.
The transmit path may include a similarly arranged second folded optical path from the laser emitter to the range finder axis, although in this case no lens is required. The second folded optical path may be formed by two or more mirrors inclined at an angle of between 50 to 60 degrees to the rangefinder axis. One or more mirrors may be adjustable with respect to the rangefinder module to adjust focus and or alignment.
Preferably the laser rangefinder is positioned within the laser rangefinder module such that the laser beam, before being redirected, is emitted in a plane that is substantially parallel to a plane of a generally flat-bodied portable device, when the module is mounted on that portable device.